Spread half of the French bread cubes onto the bottom of the 9x 13 pan. Sprinkle with half of the raisins. Cover with remaining bread cubes. Sprinkle remaining raisins on top.
Mix eggs, 3 cups Lactaid(R) whole milk, 1 teaspoon cinnamon, white sugar, and vanilla together in a large bowl with an electric mixer until ingredients are well blended, 2 to 3 minutes. Pour over bread mixture in pan.
Gently press down bread so it is slightly covered by the liquid. Cover with plastic wrap and put in the refrigerator overnight.
Preheat oven to 350 degrees F (175 degrees C).
Remove plastic from casserole and place in the oven. Bake uncovered until set and top is golden brown, about 45 minutes.
Whisk powdered sugar, 1/4 teaspoon cinnamon, maple syrup, and 1 tablespoon Lactaid(R) milk together in a bowl. If too think, add a bit more milk. Glaze should be thick but liquid enough to drizzle.
Drizzle glaze over warm casserole. Allow glaze to thicken and set before serving, about 10 minutes.
